One of my favorite parts of websites twenty years ago was the links. Thats where the good stuff always was!
Kunaki
I spend a TON of time on Kunaki. They make it VERY cheap and easy to produce high quality media with as few as 1 single unit.
Rate Your Music
This has become an increasingly useful resource in recent years. Chiefly because of the masterfully curated Lists that it's users compiled.
Send Back My Stamps
Incredible collection of scanned Metal Fan Zines of yesteryear!
The Metal Detektor
Simple tool to find the cheapest distro in the US carrying any metal album. I use this ALL the time.